The Collection Watercolour high quality surface sized paper is made from 100% cotton rag offering extremely strong fibers and purity. It is vegan, archival and acid-free. The durable paper surface is well suited for demanding watercolor techniques including wet-on-wet painting. The fibers do not lift, rub off or loosen, even when applying multiple layers of color. Available in cold-pressed, hot-pressed and rough. Available in two paper weights, 140 lb. (300gsm) or 300 lb. (640gsm). Ten sheets per block.